Minister of Foreign Affairs Cho Hyun briefs on results of ASEAN-related ministerial meetings during a press conference at a hotel in Manila, Philippines, Thursday (local time). Yonhap

The foreign ministry plans to change all diplomats' email addresses to prevent potential misuse following a data breach at an affiliated think tank, according to people close to the matter Thursday.

The personal information of all diplomats was presumed to have been leaked due to the data breach at an online education system run by the Korea National Diplomatic Academy (KNDA), in a suspected hacking that went unnoticed for 10 months until February this year.

The system had about 10,000 personal data records, most of which are believed to have been exposed in the hack.

The ministry is concerned that compromised data could be used for phishing or other sorts of cybercrimes, which could cause unforeseen damage and undermine credibility in diplomatic engagements.